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Monday, March 16, 2009

NGC6939 + NGC6946 in Cepheus

A beautiful pair of an open cluster and a spiral galaxy can be observed at the Cepheus constellation in the next months. Visual observers may prefere a dark site and big telescope to see faint details.

Monday, March 09, 2009

Observing Venus

Good evening everybody, this is a live report! I am now sitting behind my FS60 the small telescope of my roof observatory and I am observing the beauty of the night sky; the planet Venus. I am using a 2.8mm eyepiece giving a magnification of 126x. Venus's phase is clearly visible. The second planet of our solar system looks really big and bright (4,5 mag) at this magnification. This is an impressive view! Don't miss it! cs px

Wednesday, March 04, 2009

The comet Lulin (videoclip)

Hi folks, ich have just uploaded a small video clip of Lulin on my server: http://de.astrodigital.net/animationen/animationen.html
This video clip is a short one. Anyway, it clearly shows the comet's motion in the firmament.

Sunday, March 01, 2009

Periodic error of a NJP JP-Z mount

Do you know PEMPro? You can measure the quality of the worm inside your mount with it. Although PEMPro offers much more functionality than worm measurement I will stay on that, since I measured the worm of a Takahashi JPZ mount with it.
Note: The peaks on the quasi sinus curve are due to bad local seeing conditions. The periodic error (PE) of this mount seems to be +2.8 to 3.5 arcseconds. Wow!

UNGUIDED
Example 1: This is the area around the Horse Head nebula in Orion (530mm focal length, color camera with 7.8mu pixels). The JPZ mount was totally unguided for 15 minutes!

Example 2: This is the area around the star Deneb in Cygnus at a resolution of 3.26 arcsec per pixel (560mm focal length, 9 mu pixels. The JPZ mount was totally unguided for 20 minutes!

GUIDED
Please find attached the guiding curve (in fact this is a guiding ... line!) of this Takahashi NJP JPZ. The mount was guided by a binned 2x2 Starlight Lodestar camera on a Takahashi FS-60C (f/5.9) scope with the software MaximDL

What does such a guiding line really mean at night under the stars? The following astrophoto has been taken at 530mm focal length with an unmodified Canon 7D camera.

Photo of the comet Lulin C/2007 N3